The source file is GHC.Prim.hi-boot, which is just
copied to make GHC.Prim.hi
- Classes: CCallable, CReturnable
-
GHC.Base Classes: Eq, Ord, Functor, Monad
Types: list, (), Int, Bool, Ordering, Char, String
Other Prelude modules are much easier with fewer complex dependencies.
\begin{code}
-{-# OPTIONS -fno-implicit-prelude #-}
+{-# OPTIONS_GHC -fno-implicit-prelude #-}
-----------------------------------------------------------------------------
-- |
-- Module : GHC.Base
#include "MachDeps.h"
+-- #hide
module GHC.Base
(
module GHC.Base,
x /= y = not (x == y)
x == y = not (x /= y)
+-- | The 'Ord' class is used for totally ordered datatypes.
+--
+-- Instances of 'Ord' can be derived for any user-defined
+-- datatype whose constituent types are in 'Ord'. The declared order
+-- of the constructors in the data declaration determines the ordering
+-- in derived 'Ord' instances. The 'Ordering' datatype allows a single
+-- comparison to determine the precise ordering of two objects.
+--
+-- Minimal complete definition: either 'compare' or '<='.
+-- Using 'compare' can be more efficient for complex types.
+--
class (Eq a) => Ord a where
compare :: a -> a -> Ordering
(<), (<=), (>), (>=) :: a -> a -> Bool
max, min :: a -> a -> a
- -- An instance of Ord should define either 'compare' or '<='.
- -- Using 'compare' can be more efficient for complex types.
-
compare x y
| x == y = EQ
| x <= y = LT -- NB: must be '<=' not '<' to validate the
-}
class Monad m where
- (>>=) :: m a -> (a -> m b) -> m b
- (>>) :: m a -> m b -> m b
+ (>>=) :: forall a b. m a -> (a -> m b) -> m b
+ (>>) :: forall a b. m a -> m b -> m b
+ -- Explicit for-alls so that we know what order to
+ -- give type arguments when desugaring
return :: a -> m a
fail :: String -> m a
----------------------------------------------
\begin{code}
+-- | 'foldr', applied to a binary operator, a starting value (typically
+-- the right-identity of the operator), and a list, reduces the list
+-- using the binary operator, from right to left:
+--
+-- > foldr f z [x1, x2, ..., xn] == x1 `f` (x2 `f` ... (xn `f` z)...)
+
foldr :: (a -> b -> b) -> b -> [a] -> b
-- foldr _ z [] = z
-- foldr f z (x:xs) = f x (foldr f z xs)
go [] = z
go (y:ys) = y `k` go ys
+-- | A list producer that can be fused with 'foldr'.
+-- This function is merely
+--
+-- > build g = g (:) []
+--
+-- but GHC's simplifier will transform an expression of the form
+-- @'foldr' k z ('build' g)@, which may arise after inlining, to @g k z@,
+-- which avoids producing an intermediate list.
+
build :: forall a. (forall b. (a -> b -> b) -> b -> b) -> [a]
{-# INLINE [1] build #-}
-- The INLINE is important, even though build is tiny,
build g = g (:) []
+-- | A list producer that can be fused with 'foldr'.
+-- This function is merely
+--
+-- > augment g xs = g (:) xs
+--
+-- but GHC's simplifier will transform an expression of the form
+-- @'foldr' k z ('augment' g xs)@, which may arise after inlining, to
+-- @g k ('foldr' k z xs)@, which avoids producing an intermediate list.
+
augment :: forall a. (forall b. (a->b->b) -> b -> b) -> [a] -> [a]
{-# INLINE [1] augment #-}
augment g xs = g (:) xs
----------------------------------------------
\begin{code}
+-- | 'map' @f xs@ is the list obtained by applying @f@ to each element
+-- of @xs@, i.e.,
+--
+-- > map f [x1, x2, ..., xn] == [f x1, f x2, ..., f xn]
+-- > map f [x1, x2, ...] == [f x1, f x2, ...]
+
map :: (a -> b) -> [a] -> [b]
map _ [] = []
map f (x:xs) = f x : map f xs
-- append
----------------------------------------------
\begin{code}
+-- | Append two lists, i.e.,
+--
+-- > [x1, ..., xm] ++ [y1, ..., yn] == [x1, ..., xm, y1, ..., yn]
+-- > [x1, ..., xm] ++ [y1, ...] == [x1, ..., xm, y1, ...]
+--
+-- If the first list is not finite, the result is the first list.
+
(++) :: [a] -> [a] -> [a]
(++) [] ys = ys
(++) (x:xs) ys = x : xs ++ ys
\begin{code}
data Int = I# Int#
--- ^A fixed-precision integer type with at least the range @[-2^29
--- .. 2^29-1]@. The exact range for a given implementation can be
--- determined by using 'minBound' and 'maxBound' from the 'Bounded'
--- class.
+-- ^A fixed-precision integer type with at least the range @[-2^29 .. 2^29-1]@.
+-- The exact range for a given implementation can be determined by using
+-- 'Prelude.minBound' and 'Prelude.maxBound' from the 'Prelude.Bounded' class.
zeroInt, oneInt, twoInt, maxInt, minInt :: Int
zeroInt = I# 0#
%*********************************************************
\begin{code}
--- identity function
+-- | Identity function.
id :: a -> a
id x = x
lazy :: a -> a
lazy x = x
--- Assertion function. This simply ignores its boolean argument.
--- The compiler may rewrite it to (assertError line)
+-- Assertion function. This simply ignores its boolean argument.
+-- The compiler may rewrite it to @('assertError' line)@.
+
+-- | If the first argument evaluates to 'True', then the result is the
+-- second argument. Otherwise an 'AssertionFailed' exception is raised,
+-- containing a 'String' with the source file and line number of the
+-- call to 'assert'.
+--
+-- Assertions can normally be turned on or off with a compiler flag
+-- (for GHC, assertions are normally on unless the @-fignore-asserts@
+-- option is given). When assertions are turned off, the first
+-- argument to 'assert' is ignored, and the second argument is
+-- returned as the result.
+
-- SLPJ: in 5.04 etc 'assert' is in GHC.Prim,
-- but from Template Haskell onwards it's simply
-- defined here in Base.lhs
assert :: Bool -> a -> a
assert pred r = r
--- constant function
+-- | Constant function.
const :: a -> b -> a
const x _ = x
--- function composition
+-- | Function composition.
{-# INLINE (.) #-}
(.) :: (b -> c) -> (a -> b) -> a -> c
(.) f g x = f (g x)
--- flip f takes its (first) two arguments in the reverse order of f.
+-- | @'flip' f@ takes its (first) two arguments in the reverse order of @f@.
flip :: (a -> b -> c) -> b -> a -> c
flip f x y = f y x
--- right-associating infix application operator (useful in continuation-
--- passing style)
+-- | Application operator. This operator is redundant, since ordinary
+-- application @(f x)@ means the same as @(f '$' x)@. However, '$' has
+-- low, right-associative binding precedence, so it sometimes allows
+-- parentheses to be omitted; for example:
+--
+-- > f $ g $ h x = f (g (h x))
+--
+-- It is also useful in higher-order situations, such as @'map' ('$' 0) xs@,
+-- or @'Data.List.zipWith' ('$') fs xs@.
{-# INLINE ($) #-}
($) :: (a -> b) -> a -> b
f $ x = f x
--- until p f yields the result of applying f until p holds.
+-- | @'until' p f@ yields the result of applying @f@ until @p@ holds.
until :: (a -> Bool) -> (a -> a) -> a -> a
until p f x | p x = x
| otherwise = until p f (f x)
--- asTypeOf is a type-restricted version of const. It is usually used
--- as an infix operator, and its typing forces its first argument
+-- | 'asTypeOf' is a type-restricted version of 'const'. It is usually
+-- used as an infix operator, and its typing forces its first argument
-- (which is usually overloaded) to have the same type as the second.
asTypeOf :: a -> a -> a
asTypeOf = const
%*********************************************************
%* *
-\subsection{CCallable instances}
-%* *
-%*********************************************************
-
-Defined here to avoid orphans
-
-\begin{code}
-instance CCallable Char
-instance CReturnable Char
-
-instance CCallable Int
-instance CReturnable Int
-
-instance CReturnable () -- Why, exactly?
-\end{code}
-
-
-%*********************************************************
-%* *
\subsection{Generics}
%* *
%*********************************************************
-- Note that these wrappers still produce undefined results when the
-- second argument (the shift amount) is negative.
-shiftL#, shiftRL# :: Word# -> Int# -> Word#
-
+-- | Shift the argument left by the specified number of bits
+-- (which must be non-negative).
+shiftL# :: Word# -> Int# -> Word#
a `shiftL#` b | b >=# WORD_SIZE_IN_BITS# = int2Word# 0#
| otherwise = a `uncheckedShiftL#` b
+-- | Shift the argument right by the specified number of bits
+-- (which must be non-negative).
+shiftRL# :: Word# -> Int# -> Word#
a `shiftRL#` b | b >=# WORD_SIZE_IN_BITS# = int2Word# 0#
| otherwise = a `uncheckedShiftRL#` b
-iShiftL#, iShiftRA#, iShiftRL# :: Int# -> Int# -> Int#
-
+-- | Shift the argument left by the specified number of bits
+-- (which must be non-negative).
+iShiftL# :: Int# -> Int# -> Int#
a `iShiftL#` b | b >=# WORD_SIZE_IN_BITS# = 0#
| otherwise = a `uncheckedIShiftL#` b
+-- | Shift the argument right (signed) by the specified number of bits
+-- (which must be non-negative).
+iShiftRA# :: Int# -> Int# -> Int#
a `iShiftRA#` b | b >=# WORD_SIZE_IN_BITS# = if a <# 0# then (-1#) else 0#
| otherwise = a `uncheckedIShiftRA#` b
+-- | Shift the argument right (unsigned) by the specified number of bits
+-- (which must be non-negative).
+iShiftRL# :: Int# -> Int# -> Int#
a `iShiftRL#` b | b >=# WORD_SIZE_IN_BITS# = 0#
| otherwise = a `uncheckedIShiftRL#` b
#-}
\end{code}
+
+#ifdef __HADDOCK__
+\begin{code}
+-- | A special argument for the 'Control.Monad.ST.ST' type constructor,
+-- indexing a state embedded in the 'Prelude.IO' monad by
+-- 'Control.Monad.ST.stToIO'.
+data RealWorld
+\end{code}
+#endif
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